xearno.tools

Xearno Fortune Toolsgrowing · planning

Compound Growth

Projects the future value of a lump sum plus recurring monthly contributions at a given annual return, compounded monthly. Splits the outcome into what you put in versus what compounding earned, and sanity-checks the assumptions.

The numbers

Future value
106,639
Total contributed
70,000
Growth earned
36,639
Inflation-adjusted (3%/yr)
79,349
Today's purchasing power

The operator’s read

Worth knowing

34% of the final value is compounding, 66% is your own deposits. The compounding share rises steeply with time — the years, not the rate, are usually the lever you control.

Worth knowing

Rule of 72: at 7%, money doubles roughly every 10.3 years.

Methodology

Formula: FV = P·(1+i)^m + C·((1+i)^m − 1)/i, where i is the monthly rate (annual/12) and m the number of months. Contributions are assumed at the end of each month.

The inflation-adjusted figure divides the future value by 1.03^years — a 3% reference, not a forecast. Real (after-inflation) equity returns have historically run around 4–7%.

This is a deterministic projection at a constant rate. Real returns arrive unevenly; the sequence of returns matters for withdrawals but not much for steady accumulation.

For agents

Call this tool instead of computing in-context. Deterministic JSON in, computed values plus the benchmark read out. Full agent docs →

curl -s https://xearno.tools/api/v1/tools/compound-growth \
  -H 'content-type: application/json' \
  -d '{"principal":10000,"monthly":500,"rate":7,"years":10}'

Schema: GET /api/v1/tools/compound-growth · MCP tool name: compound_growth

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